In an image sensor, an electrical signal obtained by photoelectric conversion of a pixel is subjected to AD (Analog to Digital) conversion in an ADC (Analog to Digital Converter), and the AD conversion result is output as a pixel value.
As a method of reducing a noise included in the pixel value output from the image sensor as mentioned above, there is a method of obtaining a plurality of AD conversion results of the electrical signal output from the pixel and outputting an average value of the plurality of AD conversion results as a pixel value (see, for example, Patent Document 1).
Patent Document 1: Japanese Patent Application Laid-open No. 2009-296423